Photolithography (or lithography) is frequently used in manufacturing semiconductor integrated circuits (IC). In a typical lithography process, a resist film is spin-coated on a surface of a silicon wafer and is subsequently exposed and developed to form a pattern for etching the silicon wafer. As semiconductor fabrication technology continues to scale down where functional density has generally increased while geometry size has generally decreased, there has been a demand for a reduction in resist film thickness and a better reflectivity control during exposure. Accordingly, some new material and/or new techniques in lithography have been developed. For example, some lithography processes use silicon-containing resist over a carbon-containing bottom anti-reflective coating (BARC) layer to reduce resist film thickness. For another example, some lithography processes use a tri-layer stack that includes a resist over a silicon-containing BARC layer over a carbon-containing BARC layer. However, these approaches present new challenges.
For example, in the tri-layer approach, the silicon-containing material is intrinsically unstable and easily gels by forming crosslinks therein. The equipment that handles the material must undergo frequent cleaning processes to avoid being clogged. Unfortunately, the existing cleaning compositions are not effective in removing the cross-linked silicon-containing material. This unavoidably reduces lithography productivity. Accordingly, an improved cleaning composition and cleaning processes are needed.